NOTES ON SNAKES IN EAST AFRICA 817 
in their native haunts. It is far otherwise, however, for on 
one occasion, whilst cleaning out the case in which some were 
confined, three of these creatures were released on a piece 
of ground covered with short grass. The two larger ones 
measuring 8 feet 8 inches were secured readily enough, but 
three of us searched for nearly ten minutes before the writer 
discovered that he was standing right over the missing snake, 
which was twisted in and out of the grass and lying motion- 
less right between his shoes. 
All the four species of Night Adders ( Causus ) are found 
in East Africa ; they are much the same size as an English 
adder, but differ somewhat in habits, as they become most 
active towards dusk. The Rhombic Night Adder ((7. 
rhombeatus) is extremely common in Nairobi, and when 
disturbed crossing the road, as is often the case, it coils itself 
up and displays a vicious disposition ; if unmolested it sails 
off with the neck flattened out and the head raised about 
five inches from the ground. Both in a wild state and in 
captivity it feeds well on young Square-marked Toads ( Bujo 
regularis) and mice. The day-time is spent in rubbish-heaps, 
piles of old stones, or among the litter of outbuildings, whither 
it has gone in search of its prey. 
A specimen of Causus resimus was killed on Makindu 
platform (Uganda Railway) just as our troop-train came in. 
It is uncommon in the Mombasa coastal region and about 
Mount Elgon, from which places the writer has examined many 
specimens. The Snouted Night Adder ( C . de Filippi) seems 
to be uncommon, though no less than ten specimens were 
found preserved in a German house near Morogoro ; the 
writer has only captured two examples during twelve months’ 
residence in the neighbourhood. The still scarcer Lichten- 
stein’s Night Adder ( C . Lichtensteinii) was found at Yala 
river, British East Africa, but the writer has not as yet had 
any living specimens in captivity. 
A very interesting group of vipers are the tree-haunting 
species ( Athens ) ; if it were not for their triangular heads 
and waspish ways one would never suppose these active and 
brilliant-green snakes to be vipers at all. The writer kept 
a specimen of Athens squamiger in captivity for some months, 
